There were no climate change protesters waiting to jeer as the chief executives and other senior figures of one of the world's biggest industries gathered on Wednesday. Yet they represented a business that produces more than 5% of mankind's carbon dioxide emissions. And they were in Brussels to discuss climate change.

The summit was not called by the aviation industry - that is comparatively clean in comparison. Nor was it made up of car makers, oil companies, shipping firms or any other business that has traditionally drawn the fire of green campaigners.

These chief executives deal in a more down-to-earth commodity: cement. It is the key ingredient in concrete, and one that is rapidly emerging as a major obstacle on the world's path to a low-carbon economy.

No company will make carbon-neutral cement any time soon. The manufacturing process depends on burning vast amounts of cheap coal to heat kilns to more than 1,500C. It also relies on the decomposition of limestone, a chemical change which frees carbon dioxide as a byproduct. So as demand for cement grows, for sewers, schools and hospitals as well as for luxury hotels and car parks, so will greenhouse gas emissions. Cement plants and factories across the world are projected to churn out almost 5bn tonnes of carbon dioxide annually by 2050 - 20 times as much as the government has pledged the entire UK will produce by that time.

Dimitri Papalexopoulos, managing director of Titan Cement, Athens, who attended the meeting, said: "No matter what you do, cement production will always release carbon dioxide. You can't change the chemistry, so we can't achieve spectacular cuts in emissions.

"Cement is needed to satisfy basic human needs, and there is no obvious substitute, so there is a trade-off between development and sustainability."

Concrete is the second most used product on the planet, after water, and almost half of it is produced in China. The booming Chinese economy has created such a demand for building materials that cement production there last year released 540m tonnes of carbon dioxide - just short of Britain's total output from all sources. Cement's weight and low value mean it is almost always made close to where it is needed, and China's demand helped it to overtake the US as the world's leading polluter last year.

Like the aviation industry, the expected rapid growth in cement production is at severe odds with calls to cut carbon emissions to tackle global warming.

Cement plants in Europe already face pollution caps under the emissions trading scheme. With no obvious way to significantly clean up their act, the companies are nervous about future regulation. So they have taken the unusual collective step of drawing attention to their damaging impact.

Mr Papalexopoulos said: "Unlike the airlines, cement is not directly visible to the consumer, so cement companies don't have the same profile. I call it enlightened self-interest. We know there is an issue. If we draw attention to ourselves then we could attract criticism, but we could also have a voice in the regulatory solutions. Otherwise we could have something thrust upon us."

The Brussels meeting brought together the heads and senior staff of 18 companies which make more than 40% of the world's cement. Howard Klee, who coordinates the initiative called the Cement Sustainability Initiative (CSI), denies it is an industrial lobby group. He said: "We have issues that affect our industry, and these companies are talking about what they might do to prepare for them.

"Most people are not even aware that making cement produces carbon dioxide. It is an incredibly low-profile business and power companies, transportation and airlines get much more attention. But if producing carbon dioxide starts to cost businesses money, it looks like it will have a huge impact on [cement companies'] financial performance."

Already, some cement companies have taken steps to reduce their environmental impact. Some burn waste products alongside coal, while others have reworked their recipes and tried to make their plants more energy-efficient, with modest success. The CSI companies are working to standardise such techniques and to issue guidelines on how they can be adopted by others, and plan to publish a progress report in February.

Like George Bush, the CSI prefers voluntary goals and reductions in the "energy intensity" of its products, rather than fixed emission targets. The Japanese company Taiheiyo has pledged to reduce the amount of carbon dioxide it emits for each tonne of cement by 3% by 2010 - a saving that will be swamped by the expected increase in production.

Michio Kimura, chairman of Taiheiyo, said: "Without a [binding] cap then emissions will go up. But we must stop production to meet a cap and that is not good for business. We focus on energy intensity, better performance for the industry and technology." In the long term, only carbon capture and storage could significantly reduce cement emissions, and the industry sponsors research into how this could be done.

Mr Kimura said companies in developing countries needed to develop cleaner technology so it could be used by cement manufacturers in China, none of which have accepted invitations to join the CSI. But many of the newer cement plants in China are cleaner than more established facilities elsewhere, such as in the US - also not represented by the initiative.

Mr Papalexopoulos said: "Sustainability is always talked about from an ethical perspective, which is right, but we also need to look at sustainability based on a business rationale. Regional caps such as the European scheme create an uneven playing field and have unintended consequences.

"Does it make sense from an environmental perspective to cap cement production in Europe, and for cement companies in Europe to shift production to North Africa, where there are less stringent controls? This a global problem, not a regional one. Our industry is trying to develop a global sector approach, which we believe would be better."

· This article was amended on Tuesday October 16 2007. We lost some decimal places when we said that cement production in China produced 540,000 tonnes of carbon dioxide last year. The figure was 540 million tonnes. This has been corrected.

· The following clarification was printed in the Guardian's Corrections and clarifications column, Monday October 29 2007. In this article about pollution and the cement industry we said that US cement plants are not represented by the Cement Sustainability Initiative (CSI). Ash Grove Cement based in Kansas has been a member of the CSI since 2006.